net: convert sk_buff_fclones.fclone_ref from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 90cbd86..d0b9f38 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -915,7 +915,7 @@ struct sk_buff_fclones {
struct sk_buff skb2;
- atomic_t fclone_ref;
+ refcount_t fclone_ref;
};
/**
@@ -935,7 +935,7 @@ static inline bool skb_fclone_busy(const struct sock *sk,
fclones = container_of(skb, struct sk_buff_fclones, skb1);
return skb->fclone == SKB_FCLONE_ORIG &&
- atomic_read(&fclones->fclone_ref) > 1 &&
+ refcount_read(&fclones->fclone_ref) > 1 &&
fclones->skb2.sk == sk;
}